Conventions

The Coding Standards document describes the coding standards for the Symfony
projects and the internal and third-party bundles. This document describes
coding standards and conventions used in the core framework to make it more
consistent and predictable. You are encouraged to follow them in your own
code, but you don't need to.

When an object has a "main" many relation with related "things"
(objects, parameters, ...), the method names are normalized:

get()

set()

has()

all()

replace()

remove()

clear()

isEmpty()

add()

register()

count()

keys()

The usage of these methods are only allowed when it is clear that there
is a main relation:

a CookieJar has many Cookie objects;

a Service Container has many services and many parameters (as services
is the main relation, the naming convention is used for this relation);

a Console Input has many arguments and many options. There is no "main"
relation, and so the naming convention does not apply.

For many relations where the convention does not apply, the following methods
must be used instead (where XXX is the name of the related thing):

Main Relation

Other Relations

get()

getXXX()

set()

setXXX()

n/a

replaceXXX()

has()

hasXXX()

all()

getXXXs()

replace()

setXXXs()

remove()

removeXXX()

clear()

clearXXX()

isEmpty()

isEmptyXXX()

add()

addXXX()

register()

registerXXX()

count()

countXXX()

keys()

n/a

Note

While "setXXX" and "replaceXXX" are very similar, there is one notable
difference: "setXXX" may replace, or add new elements to the relation.
"replaceXXX", on the other hand, cannot add new elements. If an unrecognized
key is passed to "replaceXXX" it must throw an exception.

From time to time, some classes and/or methods are deprecated in the
framework; that happens when a feature implementation cannot be changed
because of backward compatibility issues, but we still want to propose a
"better" alternative. In that case, the old implementation can simply be
deprecated.

A feature is marked as deprecated by adding a @deprecated phpdoc to
relevant classes, methods, properties, ...:

/** * @deprecated Deprecated since version 2.8, to be removed in 3.0. Use XXX instead. */

The deprecation message should indicate the version when the class/method was
deprecated, the version when it will be removed, and whenever possible, how
the feature was replaced.

A PHP E_USER_DEPRECATED error must also be triggered to help people with
the migration starting one or two minor versions before the version where the
feature will be removed (depending on the criticality of the removal):

@trigger_error('XXX() is deprecated since version 2.8 and will be removed in 3.0. Use XXX instead.',E_USER_DEPRECATED);

Without the @-silencing operator, users would need to opt-out from deprecation
notices. Silencing swaps this behavior and allows users to opt-in when they are
ready to cope with them (by adding a custom error handler like the one used by
the Web Debug Toolbar or by the PHPUnit bridge).